Abstract: The numerical model for pump light distribution of laser diode array( LDA) side-pumped laser rod was set up, the characteristics of pump light distribution in crystal of Nd∶YAG were analyzed in detail based on that model.The analysis results could be theoretical guidance for optimization in LDA side-pumped solid state laser designing, optimization and experiment. Several parameters which may influence the pump light distribution were discussed, such as the distance between bars, the thickness of glass tube and the radius of laser rod. Based on these numerical analyses, the pump parameters of LDA sidepumped solid state laser were optimized.The optimized analyzing results show that while the rod diameter is 4 mm,the bar distance is 0.4 mm,the glass tube thickness is 1 mm and the water thickness is 1 mm under the circumstance of 2 mm pump distance, we could obtain that the relative pump intensity in the center of the crystal is 40.8%,and the distribution near the axis of crystal is a relatively large homogeneous area.